In U.S. Pat. No. 4,311,082 for GENERAL PURPOSE AUTOMATIC WEAPON SYSTEM, issued Jan. 19, 1982, a gas operated, fully automatic weapon system with a dual feed mechanism is disclosed. In column 5, lines 28 through 35, the patent describes how the weapon can generally be adapted to receive different size ammunition. However, the machine gun taught therein is basically designed to fire 0.50 caliber ammunition, making the conversion to fire a 0.60 caliber and 20 mm caliber ammunition difficult and complicated, because of the larger size of the this ammunition relative to 0.50 caliber ammunition. In converting the weapon system to fire different calibers of ammunition, it is desirable that the basic weapon frame shown in FIG. 8 of the patent be utilized, and that as few parts as possible be necessarily replaced in converting the system. This constraint requires that the same feeder space be used for all ammunition calibers desired to be fired in the weapon. Accordingly, this presents a problem in feeding larger diameter and longer cartridges relative to the 0.50 caliber ammunition, in the same space allotted for the latter.
The present invention overcomes the problems in the prior art weapon systems, by providing for a cartridge feeder apparatus and method of feeding that permits 0.60 caliber and 20 mm cartridges to be placed in proper alignment for feeding into the chamber by the gun bolt as the latter moves forward. The present inventive mechanism includes means for positioning cartridges from a horizontal to an angular plane upon a pedestal means within the same space available for the 0.50 caliber ammunition, whereby when the gun bolt is moved forward it pushes the larger cartridges directly into the chamber of the barrel, the profile of the pedestal means providing a changing angular orientation of the cartridge as it is pushed forward.